Purpose:
Keratoconus (KCN), the most common corneal degeneration, can cause significant visual impairment due to astigmatism and corneal scarring, but can be treated non-surgically if detected at early stages. Patients with poor access to care may present at an older age, with blindness and require surgery.

Methods:
To estimate the prevalence of KCN and presentation of legal blindness in an urban, underserved population, a retrospective IRB-approved chart review of new patient encounters (from 2006-2011) at Nashville General County Eye Clinic was performed. Data were analyzed by descriptive statistics. Of a total 4700 new patients, 34 had KCN (identified by ICD-9 codes 371.6x). Patients were stratified by age, gender, race, best-corrected vision, and need for surgical treatment. Any associated socioeconomic, medical, or environmental factors were identified.

Results:
The prevalence of KCN over 5 years in this underserved population was 0.7%, which was statistically significant (p<0.001) compared to the documented U.S. prevalence of 0.054%. Average age at presentation was 33.32 ± 11.94 (range 25 to 41 years). By race, 5.9% identified as Caucasian, 76.5% as African-American, 14.7% Hispanic, and 2.9% of other ethnicities. Females comprised 26.5% and males 73.5%. 44.1% of patients were incarcerated and 26.4% were uninsured. Prior ocular/head trauma was endorsed by 42.9%. Legal blindness was seen in 32.4% of right eyes, and 38.2% of left eyes. Most of the patients had no associated medical co-morbidities. Seasonal allergies were present in 5.9%. All patients received treatment, with 35.3% requiring corneal transplantation surgery.

Conclusions:
Patients in this underserved population exhibit a higher prevalence of KCN than the general US population and required surgical treatment at initial presentation. Nationally, surgery is required in less than 20% of all patients with KCN. Patients with advanced disease tended to be older, uninsured or incarcerated, and endorse a history of prior ocular trauma. Few reported seasonal allergies.